Rock drill



L. A. HARRISON Nov. 10, 1925- ROCK DRILL Filed Oct. 24 1924 PatentedNov. 19, 1925.

UNITED STATES LUCIUS A. HARRISON, OF HESPERUS, COLORADO.

ROCK DRILL.

Application filed October 24, 1924. Serial No. 745,647.

To all whom it may concern:

Be it known that I, LUoIUs A. HARnIsoN, a citizen of the United States,residing at Hesperus, in the county of La Plata and State of Colorado,have invented certain new and useful Improvements in Rock Drills, ofwhich the following is a specification.

The present invention appertains to a rock drill and has for its primeobject to provide a drill which is simple and efficient in constructionreliable, strong, durable and well adapted to the purpose for which itis designed.

A particular object of the invention is to provide a drill which in itsoperation will form a cone in the rock and then crush the cone so thatthe work may be accomplished more easily than with the ordinary drillnow in use.

Vith the above and numerous other objects in view as will appear as thedescription proceeds, the invention resides in certain novel features ofconstruction, and in the combination and arrangement of parts as will behereinafter more fully described and claimed.

In the drawing:

Figure 1 is an elevation of the drill bit embodying the features of myinvention,

Figure 2 is another elevation thereof taken at right angles from thatshown in Figure 1,

Figure 3 is an end elevation thereof, and

Figure 4 is another end elevation thereof.

Referring to the drawing in detail it will be seen that 1 designates theshank or body of the drill bit which is provided with a longitudinallyextending bore indicated at 2 extending from end to end. The end 3 ofthe shank is the cutting end and the diameter thereof is greater thanthe other end. This end 3 is provided with the cutting blade as will behereinafter more fully described.

In the present instance there are four cutting blades 5 arranged inpairs, those of one pair being indicated by the numerals 4 and those ofthe other pair by the numerals 5. The cutting blades 4 are provided withcurved cutting edges indicated specifically at 6. These edges are notonly curved longitudinally but also transversely as will be appreciatedby referring to Figures 1 and 4. The under surfaces of the blades 4 aredished out as is indicated at 7 so as to be substantially concaved. Theedges 6 are senn-clrcular in formation and the ends thereof terminate adistance from each other. Between the blades 4 and adjacent the endsformation which may be chucked up through the bore 2 if desired.

It is thought that the construction, advantages, and operation of thisbit will now be clearly understood by those skilled in the art without amore detail description thereof. It is desired, however, that changes inthe details of construction, material, and in the combination andarrangement of parts may be resorted to without departing from thespirit or scope of the invention as hereinafter claimed or sacrificingany of its advantages. I

Having thus described my invention, what I claim as new is:

1. A drill bit of the class described including a shank having a pair ofspaced and opposed outer blades and a pair of spaced inner bladesdisposed transversely of and connecting the end portions of the outerblades.

2. A drill bit of the class described including a shank having a pair ofspaced and opposed outer blades and a pair of spaced inner bladesdisposed transversely of and connecting the end portions of the outerblades, said outer blades projecting below the inner blades.

3. A drill bit of the class described including a shank provided. at oneend with a plurality of pairs of blades, a pair of said blades beingcurved throughout their lengths downwardly longitudinally and outwardlytransversely, a second pair of said blades being spaced and disposedbetween and connecting the first pair of blades and extending atsubstantially right angles thereto.

In testimony whereof I aifix my signature. I

LUCIUS A. HARRISON.

